Well, he could work at Hogwarts during the summer for a change. Maybe he's helping Hagrid with the care of magical creatures. He would get to interact with new and dangerous beasts, and at the same time, he might learn some new spells to keep them in check from other professors.
Well, he might work at Weasleys' Wizard Wheezes. He could help George and Ron with inventing new products and dealing with customers. It would be full of magical mishaps and lots of fun.
In this fanfic, Harry might get a job as an Auror. He would be involved in solving magical crimes, going on dangerous missions, and working with his old friends to keep the wizarding world safe.
He could work at Weasleys' Wizard Wheezes. He has a good relationship with the Weasley family, and it would be a fun place for him to work, helping with inventing and selling all kinds of magical pranks and toys.
Obviously Harry would be one of the main characters. And Hermione might also be involved, perhaps she helps Harry get the job or gives him advice on how to do it well.
He could work at Flourish and Blotts. He's very knowledgeable about magic, so he could help customers find the right books. It would be a great job for him as he loves to read and study magic. He could also recommend books to young witches and wizards starting their magical education.
He could meet other young wizards and witches who are also working summer jobs. Maybe some from other wizarding schools.
Hagrid could be a great help. He has a lot of connections in the wizarding world, especially with those related to magical creatures. He might introduce Harry to someone who needs help with taking care of or studying magical beasts, and thus get Harry a job in that area.
Obviously, Harry would be the main character. His friends like Hermione and Ron could also be important. Hermione might help Harry with the intellectual aspects of his job, like research or paperwork.
Maybe it could be about Harry having some sort of self - discovery journey during the summer. He might start working out, change his style, and as a result, become more attractive both physically and in terms of his new - found confidence.
Well, in this fanfic, perhaps Harry realizes that the troll has been misunderstood. He gives it a job in the school kitchens. The troll could be in charge of handling the heavy pots and pans, which humans might find difficult. This job would also keep the troll away from causing trouble in the corridors.